This invention relates to a docking assembly for the extension of a guidewire with an extension wire.
It is common practice to use a guidewire for the placement of a catheter in vascular procedures such as percutaneous transluminal cardiovascular angioplasty. A guidewire typically is slightly longer than the catheter with which it is used, whereby a relatively short portion of the guidewire protrudes proximally from the catheter when the catheter is in place. If it becomes necessary to exchange the catheter, for example to increase the balloon size in an angioplasty procedure, the guidewire must be removed and replaced by an exchange wire which is about twice the length of the catheter in order to allow withdrawal of the catheter and insertion of a new catheter over the exchange wire. However, this procedure substantially complicates and slows down the vascular treatment, and there has been several attempts to attach an extension wire to the initial guidewire in order to avoid the need of exchange of the guidewire.
A docking assembly as generally described hereinabove is shown in the document EP 0 383 159 A1, in which an extendable guidewire system for vascular procedures comprises a main section with a threaded male portion at its proximal end, and an extension section which has a female connection member comprising an internal thread at its distal end and a collar at its proximal end. This female connection member is mounted on a ball configuration arranged at the distal end of the extension section, the ball configuration being located between the collar of the female connection and the internal thread, thereby assuring to the female connection a free rotation capacity. Accordingly, connection of the assembly is achieved by manually threading the rotatable female member on the male member, and disconnection is obtained by the reverse, which is easy because of the ball mounting of the female member. However, this configuration requires several turns to assure a relatively safe connection. Furthermore, the ball mounted thread connection has no self-locking capacity, whereby the risk of having the connection getting loose due to the manipulations of the guidewire during the vascular procedure.
A further docking assembly directed to a similar environment is described in U.S. Pat. No. 5,234,002 which shows a catheter exchange system in which the proximal end of a guidewire is provided with male threads and the distal end of an extension wire has a tubular member with internal female threads for meshing with the male threads of the guidewire. A connecting member forming a cylinder with an inner lumen extending therethrough is adapted to frictionally engage and secure the tubular member of the extension wire so that rotation of the connecting member causes rotation of the extension wire. The connecting member has a longitudinal slit provided through its wall and a flared entry to accommodate the proximal end of the guidewire. Connection is obtained by engaging the connecting member over the proximal end of the guidewire and rotating it to ensure meshing of the female threads at the distal end of the extension wire with the male threads at the proximal end of the guidewire. Complete engagement of the female threads over the male threads is indicated by sliding rotation of the connecting member with respect to the tubular member. Then, the connecting member must be removed and the slit thereof allows separation from the tubular member by peeling the connecting member off the tubular member. To disconnect the assembly, the extension wire must be twisted to disengage the threaded connection between it and the guidewire. This system also requires several turns to assure a relatively safe connection, however, with the additional drawback that the extension wire will be considerably twisted, hence a strong potential of getting it entangled and damaged. Furthermore, this thread connection also has no self-locking capacity; accordingly, either the assembly must be completely screwed until blocking up against some end of stroke structure or abutment, with the resulting increase in the twisting of the extension wire, or one has to accept the risk of having the connection getting loose due to manipulations of the guidewire during a vascular procedure. And removal of the connecting member by peeling it off the tubular member of the extension wire may prove difficult and delicate.
Still in a similar environment, the document WO 93/03664 shows an extendable guidewire system in which the proximal end of a guidewire is terminated by a helical coil partially loosely wound to provide gaps between adjacent coil turns, and the distal end of an extension wire is also terminated by a helical coil partially loose to provide gaps between adjacent coil turns. These coils are for alignment and rotation with respect to each other so that the respective spaced coils engage into each other. A swivel mounting of the helical coils may prevent twisting of the guidewire or extension wire. As the aligned coil engagement may easily jam in case of misalignment of the helical coils, a further embodiment provides for a guiding pin affixed to the extension wire within the corresponding helical coil, this guiding pin being dimensioned to fit inside the helical coil of the guidewire. This solution leads however to a deadlock: if the guiding pin does not fit relatively tightly within the helical coils, the connection has some flexibility, but the coils have a serious potential of jam; and if the guiding pin fits relatively tightly within the helical coils, the risk of jam is reduced, but the connection becomes rigid all along the engagement of the helical coils. And as the system has no intrinsic self-locking capacity, there remains the risk of having the connection getting loose at some moment of the vascular procedure.
Other arrangements are available. For example, the document WO 93/14805 shows a guidewire extension system comprising a turnbuckle nut formed by a tubular body in which are affixed a right-handed helically wound wire and a left-handed helically wound wire respectively defining a right-handed helical groove and a left-handed helical groove. The proximal end of the guidewire and the distal end of the extension wire are both tapered and each have a flattened tip for engagement into the grooves of the turnbuckle nut. For assembly, the flattened tips of the extension wire and guidewire are respectively engaged into the ends of the turnbuckle nut which is then rotated to cause the flattened tips to pass respectively along the left-handed helical groove and right-handed helical groove. Thus, the flattened tips of the guidewire and extension wire will meet at the ends of the helical right-handed and left-handed grooves. To disassemble the guidewire and extension wire, the turnbuckle nut must be rotated in the opposite direction in order to cause the flattened tips of the guidewire and extension wire to pass along the corresponding helical grooves until they are expelled out of the turnbuckle nut. This assembly assures a twist free connection, however, it requires a plurality of turns of the turnbuckle nut for connection and disconnection. And as it has no intrinsic self-locking capacity, it is necessary to fully wind both the tips of the guidewire and extension wire until they meet each other to achieve some friction contact between them, or to arrange for some frictional contact between the guidewire, the extension wire and the turnbuckle end edges to achieve a locking of the assembly and avoid its getting loose during a vascular procedure. Apart of this, the system does not easily permit a two-hand operation because of the need to master three elements simultaneously, whereof the need to have more people than advisable around the operating table. As a variant, the turnbuckle nut may be crimped to the distal end of the extension wire while retaining its basic function. This may facilitate a two-hand operation, however, the crimp must be precisely located in a manner allowing sufficient longitudinal play of the turnbuckle nut before groove engagement of the distal end of the extension wire in order to avoid the risk of having the proximal end of the guidewire insufficiently engaged in its corresponding groove to assure a safe connection via the turnbuckle function. This may involve complications for the expected two-hand operation.
U.S. Pat. No. 5,117,838 shows a guidewire extension system comprising an extension guidewire adapted to be releasably connected to a ground down proximal end of a guidewire. The distal end of the extension wire is mounted in a tube in which is located an open pitch flat wire coiled spring, one end of which is welded over the distal end of the extension wire, whereas the other end of the coiled spring extends freely in the tube where an end detent prevents the free end of the coiled spring to be moved out of the tube. To facilitate handling, an alignment tool in the form of a cylindrical structure with flared entries is intended to receive the tube in one end and the proximal end of the initial guidewire at the other end. To achieve connection, the ground down end of the guidewire and the tube of the extension wire are inserted into the alignment tool and the ground down end of the guidewire is pushed into the tube and urged therein until it engages the coiled flat wire spring and bottoms against the corresponding end of the extension wire. As the ground down end of the guidewire is inserted into the coils of the flat wire spring, the coils are forced to slightly uncoil and then, any axial force pulling the end of the guidewire away from the coiled spring causes its coils to move towards a smaller diameter which establishes a connection between the coils and the ground down end of the guidewire. To disconnect the assembly, it is necessary to rotate the extension wire in order to loosen the grip of the coiled spring against the ground down end of the guidewire and at the same time to pull the latter out of engagement with the coils of the spring. This assembly provides a self-locking connection which is however dependent on manipulations and skills to be disconnected and on an alignment tool for connection. To minimize the twisting of the extension wire for disconnection purposes, a further embodiment provides for swivel mounting of the tube containing the flat wire coiled spring. This configuration has, however, the disadvantage of an added mechanical complication with the risk of having the swivel tube clogging on the distal end of the extension wire.
U.S. Pat. No. 5,197,486 shows a detachable guidewire extension system in which the proximal end of the guidewire is provided with a reduced diameter rod adapted to mate with a connector socket attached to the distal end of an extension wire. This connector socket has a tubular housing containing a helical coil attached at its proximal end to the proximal end of the housing and it has an outer diameter slightly less than the inner diameter of the housing which has an inward circular lip at its distal end to prevent extension of the helical coil out of the housing. The inner diameter of the coil is less than the outer diameter of the rod at the proximal end of the guidewire. Connection of the system is achieved by urging the rod into the housing to cause the coil to expand to receive the rod. A slight rotation of the extension wire may facilitate insertion of the rod into the coil. To disconnect the assembly, it is necessary to rotate the extension wire while holding the guidewire to relax the grip of the coil on the rod and to separate the guidewire and extension wire while doing so. This is substantially the same operation as in the first embodiment of U.S. Pat. No. 5,117,838 described hereinbefore. As with this configuration, there is a self-locking connection which is dependent on manipulations and skills to be disconnected, in particular because of the need to rotate the extension wire while pulling it out of the housing.
U.S. Pat. No. 5,109,867 shows extendable guidewire assemblies comprising axial interlocking members respectively fastened to corresponding ends of the guidewire and guidewire extension, and a retractable spring biased sleeve which has to be retracted to permit the interlocking members to be interlocked, which sleeve has then to be extended to enclose the interlocked members in order to maintain them in interlocked conditions. To lock the assembly, it is therefore necessary to first retract the sleeve to fully free one of the interlocking members, then to place another interlocking member in interlocking condition with respect to the first interlocking member, and finally to allow the spring biased sleeve to move over the interlocked members to maintain the interlocked assembly. To unlock the system, it is sufficient to retract the sleeve up to freeing both the interlocking members in order to separate them. The system is shown in various embodiments in which the interlocking is obtained by overlapping two coiled members, or by inserting a ball into expandable tongues, or by overlapping hook-like members, or still by inserting a cylindrical head into a slotted bore. Apart from the multiplicity of elements which may clog or jam, these interlocking systems may prove difficult to operate because of the need to retract the spring biased sleeve for interlocking the interlocking members. A two-hand operation may be therefore hazardous, which may result in the need of having more people than otherwise needed around the patient.
U.S. Pat. No. 5,195,535 is directed to a connection system for a guidewire and guidewire extension in which the proximal end of the guidewire is terminated by a socket whereas the distal end of the guidewire extension comprises a wire having a reduced diameter end portion carrying a movable sleeve. A wedging element is affixed to the tip of the reduced diameter end portion of the wire, and a tubular handle is affixed by its distal end to the proximal end of the movable sleeve. To achieve connection, the sleeve is first withdrawn proximally over the extension wire by pulling proximally the tubular handle while maintaining or pushing the extension wire and its wedging element. The wire and sleeve are then inserted into the socket of the guidewire by pushing distally the wire and handle simultaneously. Then, holding the handle to maintain the position of the sleeve in the socket, the extension wire is pulled proximally to cause the wedging element to engage and become firmly wedged in the distal end of the sleeve. Further advancement of the wedging element in the sleeve causes the sleeve to expand radially into engagement with the inner wall of the socket, thereby assuring gripping of the sleeve in the socket. To disconnect the assembly, it is necessary to forcibly pull proximally the handle to proximally draw the sleeve out of its wedged condition between the inner surface of the socket and the wedging element. Though relatively complicated on a structural viewpoint, the system provides a strong and safe connection between guidewire and extension wire. However, it needs skills to properly connect and release the assembly. Furthermore, it does not practically permit a two-hand operation, being necessary to manipulate the handle, the extension wire, and the socket of the guidewire, whereby the need of more people than normally required around the patient.
It is an object of this invention to improve the conditions of attaching an extension wire to a guidewire and to avoid the aforesaid drawbacks. It is a further object of the invention to achieve attachment and release of a guidewire and extension wire by means of a docking assembly which is simple and advantageous to manufacture, which guarantees an efficient and safely repetitive operation for both connection and release of the assembly, which does not require skills or tooling manipulations, which is not influenced by slippery fluids and other clogging agents, and which is positive and highly versatile.
All documents cited herein, including the foregoing, are incorporated herein by reference in their entireties for all purposes.